Boto3 S3, sort bucket by last modified

Question

I need to fetch a list of items from S3 using Boto3, but instead of returning default sort order (descending) I want it to return it via reverse order.

I know you ca

Answer 1

A simpler approach, using the python3 sorted() function:

import boto3
s3 = boto3.resource('s3')

myBucket = s3.Bucket('name')

def obj_last_modified(myobj):
    return myobj.last_modified

sortedObjects = sorted(myBucket.objects.all(), key=obj_last_modified, reverse=True)

you now have a reverse sorted list, sorted by the 'last_modified' attribute of each Object.

Answer 2

Slight improvement of above:

s3 = boto3.resource('s3')
my_bucket = s3.Bucket('myBucket')
files = my_bucket.objects.filter():
files = [obj.key for obj in sorted(files, key=lambda x: x.last_modified, 
    reverse=True)]

Answer 3

I did a small variation of what @helloV posted below. its not 100% optimum, but it gets the job done with the limitations boto3 has as of this time.

s3 = boto3.resource('s3')
my_bucket = s3.Bucket('myBucket')
unsorted = []
for file in my_bucket.objects.filter():
   unsorted.append(file)

files = [obj.key for obj in sorted(unsorted, key=get_last_modified, 
    reverse=True)][0:9]

Answer 4

s3 = boto3.client('s3')

get_last_modified = lambda obj: int(obj['LastModified'].strftime('%Y%m%d%H%M%S'))

def sortFindLatest(bucket_name):
    resp = s3.list_objects(Bucket=bucket_name)
    if 'Contents' in resp:
        objs = resp['Contents']
        files = sorted(objs, key=get_last_modified)
        for key in files:
            file = key['Key']
            cx = s3.get_object(Bucket=bucket_name, Key=file)

This works for me to sort by date and time. I am using Python3 AWS lambda. Your mileage may vary. It can be optimized, I purposely made it discrete. As mentioned in an earlier post, 'reverse=True' can be added to change the sort order.

Answer 5

it seems that is no way to do the sort by using boto3. According to the documentation, boto3 only supports these methods for Collections:

all(), filter(**kwargs), page_size(**kwargs), limit(**kwargs)

Hope this help in some way. https://boto3.readthedocs.io/en/latest/reference/services/s3.html#S3.ServiceResource.buckets

Answer 6

If there are not many objects in the bucket, you can use Python to sort it to your needs.

Define a lambda to get the last modified time:

get_last_modified = lambda obj: int(obj['LastModified'].strftime('%s'))

Get all objects and sort them by last modified time.

s3 = boto3.client('s3')
objs = s3.list_objects_v2(Bucket='my_bucket')['Contents']
[obj['Key'] for obj in sorted(objs, key=get_last_modified)]

If you want to reverse the sort:

[obj['Key'] for obj in sorted(objs, key=get_last_modified, reverse=True)]